U.S. patent application number 13/851707 was filed with the patent office on 2014-10-02 for frac pump isolation safety system.
The applicant listed for this patent is FTS INTERNATIONAL SERVICES, LLC. Invention is credited to Kevin Krebs, Nathan Meier, Coy Randle, Justin Robertshaw, Don Wade.
Application Number | 20140290768 13/851707 |
Document ID | / |
Family ID | 51619632 |
Filed Date | 2014-10-02 |
United States Patent
Application |
20140290768 |
Kind Code |
A1 |
Randle; Coy ; et
al. |
October 2, 2014 |
Frac Pump Isolation Safety System
Abstract
The improved system allows an operator overseeing a well
stimulation hydraulic fracturing operation to bring frac pumps
online and offline as necessary. A control panel allows the
operator to remain at a safe distance from high-pressure equipment,
including the frac pumps and respective remotely actuated isolation
valves, yet allows monitoring and operation of same. The operating
condition of the frac pumps and the isolation valves is monitored
by an automated processing device, which prevents operation of same
during certain pump and valve conditions. A wireless operator
interface is also provided.
Inventors: |
Randle; Coy; (Fort Worth,
TX) ; Krebs; Kevin; (Fort Worth, TX) ; Meier;
Nathan; (Fort Worth, TX) ; Robertshaw; Justin;
(Fort Worth, TX) ; Wade; Don; (Fort Worth,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FTS INTERNATIONAL SERVICES, LLC |
Fort Worth |
TX |
US |
|
|
Family ID: |
51619632 |
Appl. No.: |
13/851707 |
Filed: |
March 27, 2013 |
Current U.S.
Class: |
137/565.16 ;
137/565.11 |
Current CPC
Class: |
Y10T 137/85986 20150401;
Y10T 137/86027 20150401; E21B 43/26 20130101 |
Class at
Publication: |
137/565.16 ;
137/565.11 |
International
Class: |
E21B 43/26 20060101
E21B043/26 |
Claims
1. A high-pressure fluid delivery system having a plurality of
fluid pumps in fluid communication with a manifold to provide high
fluid pressures and high fluid volumes, the system comprising: an
isolation valve in a fluid circuit between a fluid discharge of
each of a plurality of fluid pumps and a fluid manifold, the
isolation valve capable of substantially isolating the fluid pump
discharge from the manifold, the isolation valve adapted to allow
for remote actuation; and a remote operator control panel, the
control panel in signal communication with each isolation valve and
its respective pump, the control panel adapted to monitor at least
one valve condition and at least one respective pump condition, the
isolation valve operable in response to a signal from the operator
control panel.
2. The system of claim 1, the control panel further comprising: a
graphical operator interface adapted to allow an operator to
remotely monitor the at least one valve condition or the at least
one pump condition during operations.
3. The system of claim 1, the control panel further comprising: a
graphical operator interface adapted to allow an operator to
remotely monitor the at least one valve condition or the at least
one pump condition during operations, and to effect actuation of
each isolation valve and/or operation of each pump.
4. The system of claim 1 further comprising: a graphical operator
interface in wireless communication with the control panel, the
interface adapted to allow an operator to remotely monitor the at
least one valve condition and/or the at least respective one pump
condition during operations.
5. The system of claim 1 further comprising: a graphical operator
interface in wireless communication with the control panel, the
interface adapted to allow an operator to remotely monitor the at
least one valve condition and/or the at least one respective pump
condition during operations, and to effect actuation of each
isolation valve and/or operation of each hydraulic fracturing
pump.
6. The system of claim 1 further comprising: a hydraulic or
pneumatic valve actuation system, the actuation system in fluid
communication with the isolation valves for isolation valve
actuation, the actuation system in further signal communication
with the control panel to effect the isolation valve actuation.
7. The system of claim 1 further comprising: an electromechanical
valve actuation system, the actuation system in mechanical
communication with the isolation valves for isolation valve
actuation, the actuation system in further signal communication
with the control panel to effect the isolation valve actuation.
8. The system of claim 1, wherein the at least one pump condition
is an indication of the operational status of the pump, the system
further comprising: an automated processing and control device
adapted to perform the program steps for: accepting a request by
operator to close the isolation valve; if the respective pump is
not operating, closing the isolation valve; and if the respective
pump is operating, maintaining the valve open.
9. The system of claim 1, wherein the at least one valve condition
is an indication of the open or closed state of the valve, the
system further comprising: an automated processing and control
device adapted to perform the program steps for: accepting a
request by operator to engage the transmission on a hydraulic
fracturing pump; if the respective isolation valve is open,
starting the pump; and if the respective isolation valve is not
open, warning the operator of the valve condition.
10. The system of claim 1, wherein the at least one valve condition
is an indication of the open or closed state of the valve, the
system further comprising: an automated processing and control
device adapted to perform the program steps for: accepting a
request by operator to engage the transmission on a hydraulic
fracturing pump; if the respective isolation valve is open,
starting the pump; and if the respective isolation valve is not
open, automatically opening the isolation valve before starting the
pump.
11. The system of claim 1, wherein the at least one valve condition
is an indication of the open or closed state of the valve and the
at least one pump condition is an indication of the physical
integrity of the pump, the system further comprising: an automated
processing and control device adapted to perform the program steps
for: monitoring the physical integrity of the pump to determine an
adverse change in the pump operational characteristics
necessitating isolation; if the pump transmission is not
disengaged, disengaging the pump transmission; and closing the
isolation valve.
12. A hydraulic fracturing pump isolation safety system, the system
comprising: a plurality of remotely actuated isolation valves, each
isolation valve in fluid communication with the fluid head of a
hydraulic fracturing pump, the plurality of isolation valves in
further fluid communication with a manifold through which
fracturing fluid is provided to a well head; and a control panel
located remotely from the plurality of isolation valves and the
hydraulic fracturing pumps, the control panel in signal
communication with the plurality of plug valves and the hydraulic
fracturing pumps, the control panel comprising an operator
interface for monitoring by an operator of at least one valve
condition and at least one respective pump condition, wherein the
control panel is adapted to allow the operator to remotely monitor
and control each valve and/or pump in response to the monitored
conditions.
13. The system of claim 12, the system further comprising: an
automated processing device adapted to automatically monitor the
pump condition and to prevent the ability to change the operating
condition of the respective isolation valve in response to this
monitored pump condition.
14. The system of claim 12, the system further comprising: an
automated processing device adapted to automatically monitor the
isolation valve condition and to prevent the ability to change the
operating condition of the respective hydraulic fracturing pump in
response to this monitored valve condition.
15. The system of claim 12, the system further comprising: an
automated processing device adapted to automatically monitor the
first condition of a pump and to automatically operate the
respective isolation valve in response to this monitored pump
condition.
16. The system of claim 12, the control panel further comprising: a
graphical operator interface adapted to allow an operator to
remotely monitor the at least one valve condition and/or the at
least one pump condition during well stimulation operations.
17. The system of claim 12, the control panel further comprising: a
graphical operator interface adapted to allow an operator to
remotely monitor the at least one valve condition and/or the at
least one pump condition during well stimulation operations, and to
effect operation of each isolation valve and/or operation of each
hydraulic fracturing pump.
18. The system of claim 12, the system further comprising: a
graphical operator interface in wireless communication with the
control panel, the interface adapted to allow an operator to
remotely monitor the at least one valve condition and/or the at
least one pump condition during well stimulation operations.
19. The system of claim 12, the system further comprising: a
graphical operator interface in wireless communication with the
control panel, the interface adapted to allow an operator to
remotely monitor the at least one valve condition and/or the at
least one pump condition during well stimulation operations, and to
effect operation of each isolation valve and/or operation of each
hydraulic fracturing pump.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
[0003] Not Applicable
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT
DISC
[0004] Not Applicable
BACKGROUND OF THE INVENTION
[0005] 1. Field of the Invention
[0006] The present invention relates to a system for safe remote
monitoring and operation of high-pressure and high-volume
industrial fluid delivery system and, more specifically, to a
system for remote monitoring and control of hydraulic fracturing
equipment in a well stimulation operation.
[0007] 2. Description of Related Art including information
disclosed under 37 CFR 1.97 and 1.98
[0008] Horizontal drilling and well stimulation processes have
revolutionized the oil and gas industry with regard to the
optimization of hydrocarbon extraction. Shale areas once thought
unreachable are now within range of the horizontal drilling
technology, with most shale gas wells having an average depth from
the surface of between 7,500 and 13,000 feet with a horizontal run
in the pay zone of 2,000 to 3,000 feet on average, if not better.
Further, wells in shale areas that were once thought to be dry or
of limited productivity are now capable of efficient (and
profitable) production due to the use of advanced well stimulation
processes, specifically hydraulic fracturing of the well bore in
the specific hydrocarbon zones.
[0009] Every shale zone is composed differently, requiring somewhat
different drilling and well stimulation techniques to make the well
economically viable. Because of the attendant high costs of
horizontal drilling, it is necessary that such a well produce as
much hydrocarbon as possible as quickly as possible to allow the
well operator to recover these substantial upfront costs. As such,
hydraulic fracturing is used quite extensively to open up the pores
and create fissures in the surrounding shale to allow trapped
hydrocarbons to flow freely.
[0010] Rock pressures beneath the earth's surface are quite
extreme, especially given the depths to which the well holes must
be drilled to reach the pay zones. As a rule of thumb, the pressure
exerted by the surrounding rock at a depth of 10,000 feet measures
approximately 10,000 PSI, but can be as high as 15,000 PSI or
greater depending on the shale characteristics. When a well hole is
drilled to this depth and continued horizontally, this enormous
pressure is felt on the walls of the lateral run. Consequently, the
ability to fracture the surrounding shale formation requires the
ability to exceed this surrounding pressure.
[0011] Hydraulic fracturing pumps, or "frac pumps" as they are
known in the industry, are relatively massive positive displacement
pumps capable of countering this enormous pressure at these extreme
depths. Fracturing fluid ("frac fluid"), often containing proppants
and/or slickwater, is pumped downhole by the frac pump, relying on
the relative incompressibility of the frac fluid to transmit the
frac pump pressure at the surface to an adequate pressure in the
pay zone to cause the fractures and fissures to form. Thus, a frac
pump is typically called upon to continuously pump frac fluid at a
maximum pressure of around 15,000 PSI with a maximum flow rate of
over 1,132 GPM downhole, depending on the rpm and plunger size,
which requires an input power of upwards of 2,500 BHP to achieve
this kind of performance from the pump.
[0012] However, pressure is not the only requirement. Because of
the extreme distance that the frac fluid must travel, in addition
to the large number of perforations in the lateral run through
which the frac fluid must flow, a very high volumetric flow rate
must also be achieved and maintained. If not maintained for an
optimum amount of time, which is determined primarily by the shale
conditions of the well, any fissures that form might close once the
frac fluid stops flowing. If these stimulation operations are
halted before sufficient amounts of proppant are introduced into
the fissures, the fissures can close and negate any progress made
to that point. Thus, for redundancy to ensure sufficient continuous
pressures and volumes of frac fluid, it becomes necessary to
utilize multiple frac pumps during such a well stimulation
operation.
[0013] A typical hydraulic fracturing operation requires numerous
high-pressure pumps and support equipment. A blender unit supplies
massive amounts of frac fluid to the intakes of multiple
high-pressure frac pumps during operation. The discharge of each of
the frac pumps is connected to a manifold where the frac-fluid
flows are combined. The manifold is connected to a wellhead,
typically using a wellhead isolation device, directing the frac
fluids into the wellbore.
[0014] Because the frac fluid is abrasive and often corrosive,
maintenance of frac pumps must occur regularly. Also, because of
the great strains on the frac pumps, breakdowns can occur, hence
the need for redundancy. To allow for maintenance or repair, it is
necessary to isolate the particular frac pump while the others
continue to pump. However, extra precaution must be taken when
isolating a frac pump--given the extreme operating pressures
involved.
[0015] Manual isolation valves are commonly utilized between the
frac pumps and the manifold. These isolation valves require an
operator to physically locate and operate the desired valve to take
a frac pump offline for repairs or maintenance. With the valves
typically mounted in close proximity to the manifold, the operator
must therefore physically approach the manifold to locate the
appropriate isolation valve to close. However, with all of the
other pumps running, the extreme environment due to the cacophony
of noise and the mechanical vibrations of the equipment can make it
exceedingly difficult for the operator to determine which valve to
operate, or whether the respective frac pump is in a safe
condition. If the wrong valve is closed on an operating frac pump,
an essentially instantaneous overpressure and explosion of the
valve hardware, lines, and/or fluid head of the pump can occur,
possibly leading to equipment destruction, operation and production
time losses, operator injury, and attendant costs. The present
invention addresses these shortcomings as well as others as will
become apparent upon a thorough reading of the disclosure provided
herein.
BRIEF SUMMARY OF THE INVENTION
[0016] Described herein is an industrial high-pressure fluid
delivery system having a plurality of fluid pumps in fluid
communication with a manifold to provide high fluid pressures and
high fluid volumes, the system comprising: an isolation valve in a
fluid circuit between each of a plurality of fluid pumps and a
fluid manifold, the isolation valve capable of substantially
isolating the fluid pump discharge from the manifold, the isolation
valve adapted to allow for remote actuation; and a remote operator
control panel, the control panel in signal communication with each
isolation valve and its respective pump, the control panel adapted
to monitor at least one valve condition and at least one respective
pump condition, the isolation valve operable in response to a
signal from the operator control panel. Supplementary elements
forming additional embodiments include wired and/or wireless
operator interfaces, alternate means of isolation valve actuation,
and various system condition monitoring inputs.
[0017] Also described herein is a hydraulic fracturing pump
isolation safety system, the system comprising: a plurality of
remotely actuated isolation valves, each isolation valve in fluid
communication with the fluid head of a hydraulic fracturing pump,
the plurality of isolation valves in further fluid communication
with a manifold through which fracturing fluid is provided to a
well head; and a control panel located remotely from the plurality
of isolation valves and the hydraulic fracturing pumps, the control
panel in signal communication with the plurality of isolation
valves and the hydraulic fracturing pumps, the control panel
comprising an operator interface for monitoring by an operator of
at least one valve condition and at least one respective pump
condition, wherein the control panel is adapted to allow the
operator to remotely monitor and control each valve and/or pump in
response to the monitored conditions. Supplementary elements
forming additional embodiments include wired and/or wireless
operator interfaces, alternate means of isolation valve actuation,
and various system condition monitoring inputs.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0018] The present invention will be more fully understood by
reference to the following detailed description of the preferred
embodiments of the present invention when read in conjunction with
the accompanying drawings, wherein:
[0019] FIG. 1A depicts a first embodiment of the invention as it
applies to a hydraulic fracturing operation during well
stimulation, emphasizing the large amount of basic equipment
necessary for the fracturing operation;
[0020] FIG. 1B depicts a hydraulically actuated isolation valve as
used in the present embodiment;
[0021] FIG. 1C depicts a first operator controlling the system via
the remotely located control panel, with a second operator
monitoring system operation via wireless device;
[0022] FIG. 2 is a simplified flow diagram showcasing the basic
functional operating steps followed by an embodiment with regard to
remote operation of an isolation valve; and
[0023] FIG. 3 is a simplified flow diagram showcasing the basic
functional operating steps followed by an embodiment with regard to
local operation of an isolation valve.
[0024] The above figures are provided for the purpose of
illustration and description only, and are not intended to define
the limits of the disclosed invention. Use of the same reference
number in multiple figures is intended to designate the same or
similar parts. Furthermore, when the terms "top," "bottom,"
"first," "second," "upper," "lower," "height," "width," "length,"
"end," "side," "horizontal," "vertical," and similar terms are used
herein, it should be understood that these terms have reference
only to the structure shown in the drawing and are utilized only to
facilitate describing the particular embodiment. The extension of
the figures with respect to number, position, relationship, and
dimensions of the parts to form the preferred embodiment will be
explained or will be within the skill of the art after the
following teachings of the present invention have been read and
understood.
DETAILED DESCRIPTION OF THE INVENTION
[0025] FIG. 1A depicts a first embodiment of the invention as it
applies to a hydraulic fracturing operation during well
stimulation, emphasizing the large amount of basic equipment
necessary for the fracturing operation. As shown, a plurality of
hydraulic fracturing ("frac") pumps (102) is connected, each in
parallel, to a primary fluid manifold (104) to provide frac fluids
to a wellhead (112) for well stimulation as previously described.
Hydraulically actuated isolation valves (108) provide a means for
isolating a frac pump (102) from the manifold (104) to allow for
repair or maintenance of the frac pump while avoiding work
stoppage. A hydraulic control pump and reservoir (106) provide
hydraulic pressure for remote isolation valve (108) actuation. The
frac fluids are supplied to each pump (102) from a frac fluid
blender reservoir trailer (110). Remote monitoring and control of
the equipment occurs from a remote location, for example, a treater
truck (114) as depicted.
[0026] FIG. 1B depicts a hydraulically actuated isolation valve as
used in the present embodiment. In this embodiment a hydraulically
actuated plug valve is utilized as the isolation valve (108). A
plug valve uses rotational motion of a machined plug feature to
stop or start fluid flow. In the open position, a bored passage in
the plug lines up with the inlet and outlet ports of the valve body
to allow flow. However, when the plug feature is rotated from the
open position (usually 90 degrees), the bored passage no longer
aligns with the ports and the solid part of the plug blocks the
ports and stops fluid flow (with, perhaps, the exception of minor
leakage around the plug due to the valve seat and packing
tolerances). A well-known industrial hydraulic actuation means
(122) mounted on the valve utilizes external hydraulic controller
pressure to effect rotation of the valve into the open or the
closed position as desired. It is also within the scope of the
invention to utilize remote mechanical/electrical solenoid
actuation, pneumatic actuation, or some combination of hydraulic,
mechanical/electrical, and pneumatic actuation.
[0027] The isolation valve (108) also utilizes a valve position
determining means to provide a signal to the operator indicating
the condition of the valve (i.e., whether the valve is open or
closed). For example, the present embodiment utilizes isolation
valves having a physical limit switch (120) that detects the
rotational position of the plug and provides a signal representing
the valve's current condition.
[0028] Moreover, although plug valves are described in the present
embodiment, one of ordinary skill will understand and appreciate
that other types of isolation valves may be utilized and are within
the scope of the claims. For example, alternatives to plug valves
include gate, ball, and disc gate valves capable of handling the
operating pressures of the system.
[0029] Turning again to FIG. 1A, the frac pumps (102) each,
likewise, include a pump condition determining means that generates
a signal that reflects the condition or operational status of the
pump. For example, in the present embodiment, a limit switch is
utilized to provide a signal indication representing whether or not
the frac pump (102) transmission is engaged. The frac pumps utilize
a large diesel engine or electric motor that powers a drive gear to
operate the frac pump (102). If the pump transmission is
disengaged, then the frac pump (102) pistons will not reciprocate
under power and, therefore, the pump is considered offline. Other
conditions that may be monitored include the current flow through
the motor windings, fluid end pressure, temperature, sound, and/or
vibration, which can also give an indication of the overall health
and operation of the frac pump.
[0030] Another source of input to the control system is a valve to
pump connection determining means, which provides an indication
that a valve is in fluid communication with a frac pump. This can
be provided by visual indication and subsequent input by an
operator of the connectedness, or may be automated. For example,
the high-pressure fluid lines connecting the frac pump and
isolation valve are typically constructed entirely of metal or
include sufficient metal such that the line is capable of
electrical current flow. A conductivity sensor with one lead placed
on the pump and the other lead placed on the valve will provide an
indication of current flow (or electrical resistance less than
infinity) between the two devices. Thus, this may serve as a
controller input for automation purposes. Other indicators may
include the use of reflected electromagnetic waves (sound or
light), or even a separate conductive cable that must be detached
when the fluid line is detached.
[0031] FIG. 1C depicts a first operator controlling and/or
monitoring the system from a treater truck (114) via the remotely
located wired control panel (116), with a second operator
controlling and/or monitoring system operation via wireless device
(118). The remote operator control panel (116) collects the various
aforementioned signals of interest for consideration by an
equipment operator. The remote operator control panel (116) allows
the operator to interface with and control the operation of the
well stimulation system. The control panel in the present
embodiment provides a display screen that is updated with status
information regarding the monitored portions of the system and
accepts operator input to affect the condition of the frac pumps
(102), isolation valves (108), and the like. The control panel in
the present embodiment is constructed utilizing commercially
available controller programming software to construct the
graphical user interface, but other embodiments are envisioned that
utilize a proprietary interface or some combination thereof.
[0032] The remote operator control panel (116) operates in
combination with an industrial programmable logic controller
("PLC") as an automated processing device for collection and
handling of the various equipment condition and control signals.
The PLC is essentially a stored program computer with large current
handling relays that provides hard real time monitoring and control
of the system. For example, the PLC accepts as inputs the valve
condition and the pump condition, and presents the monitored
conditions to the operator control panel for display on the
operator graphical interface. Specifically, the system provides
indication of the transmission engagement condition of each of the
pumps, as well as the open or closed condition of each of the
isolation valves. Other conditions may be monitored and displayed
as desired, including line pressures, other valve conditions, frac
pump motor running conditions, fluid and hardware temperatures,
etc. One of ordinary skill will appreciate that the controller
software may be programmed to present this condition information in
any desired format. In addition, the PLC functionality may be
envisioned as a simple automated computing device (for example, a
laptop, notebook, desktop computer, industrial single board
computer, or the like) running proprietary software, or even a
programmable logic relay (PLR) device capable of accepting the
equipment condition signals for processing and generating control
signals in response to operator action or pre-programmed logic.
[0033] The control panel (116) in the present embodiment is located
at a position sufficiently remote from the frac pumps (102),
isolation valves (108), and manifold (104) to prevent potential
operator injury should an overpressure event occur. Because they
are electric, the valve and pump condition signals may be routed
over wired cables of sufficient length to allow the operator
control panel (116) to be located within a safety enclosure, for
example, in a vehicle such as a treater truck (114) or even a
reinforced building.
[0034] The control panel (116) may also utilize industrial wireless
communications for all or a portion of the equipment condition and
control signals, as well as the operator graphical interface. For
example, a portable tablet (118), smartphone, or portable computer
communicating over a wireless network may be carried by an operator
to afford additional flexibility in the monitor and control of
fracturing operation equipment. The present embodiment utilizes
packetized Wi-Fi communications with the handheld remote. However,
wireless communication may occur over any cellular or packetized
communications means, for example, 3G, 4G LTE, Bluetooth, Zigbee,
or the like, or some combination of same.
[0035] During normal operation, a desired number of pumps are
attached and running and the respective isolation valves are open.
Depending on the requirements of a particular pumping operation, up
to the maximum number of pumps may be connected to a manifold. For
example, on a manifold that allows a maximum of twelve pumps to be
connected it is not uncommon to have fewer than twelve pumps
connected to the manifold at one time. Thus, there may be one or
more isolation valves attached to the manifold without an attached
pump.
[0036] If a particular attached pump requires shutdown for
maintenance or repair, an offline backup pump may be brought online
by first engaging the backup pump transmission (with the electric
motor de-energized), opening the respective isolation valve, and
energizing the pump's motor. The frac pump to be secured may then
be de-energized (transmission engaged) and the respective isolation
valve closed when the pump's head pressure has decreased to a safe
pressure. The transmission may then be disengaged to signal the
system that the isolation valve should remain closed. System safety
interlocks prevent conditions that could cause an overpressure
event to occur.
[0037] FIG. 2 is a simplified flow diagram showcasing the basic
functional operating steps followed by an embodiment with regard to
remote operation of an isolation valve. The present embodiment
utilizes two modes of operation: local (maintenance) and remote
(normal operation). Because of the potential hazards involved
during operation, the system includes safety interlocks that
prevent local (maintenance) operation of the manifold and isolation
valves unless each of the isolation valves are disconnected from
their respective frac pumps. Thus, certain operational conditions
must be tested before operation is allowed.
[0038] Remote operation is the primary method for controlling the
high pressure pumping system during operation. As shown, upon
accepting an operator's request to operate an isolation valve (202)
the system considers a number of operating conditions. The first
test involves whether the valve for which operation is requested is
connected to a pump (204). If the valve is not connected to a pump
(204), the system displays a warning on the operating panel and
valve operation is prevented (206). If the valve is connected to a
pump (204), the system checks to ensure that the connected engine,
pump, and valves are in a known state (208). With regard to the
valves, it is important for the system to ascertain the exact
state--whether fully opened or fully closed--before operation is
allowed. A valve in an intermediate position may be an indication
of a stuck or otherwise faulty valve or actuator, or even a faulty
indicator circuit. In such a situation the system will again
display a warning to the operator and prevent valve operation (206)
until the exact conditions can be determined. Likewise, if an
engine or pump state is unknown (208) the system will display a
warning to the operator and prevent valve operation (206). If the
connected engine is not running (210) the valve operation is
allowed (212) (i.e., an open valve may be closed and a closed valve
may be opened). If the engine is running (210) and the connected
isolation valve is closed, then the system will allow the valve to
be opened (216). This condition allows for a pump to be brought
online. However, if the isolation valve was open and the remote
request was to close the valve, the system displays a warning to
the operator and maintains the valve open (218). This prevents the
operator from inadvertently closing an isolation valve during
active pumping. Engine operation may be determined by the
transmission state (i.e., forward gear engaged or disengaged) as
well engine RPM, current draw (for electrical motors), and the
like.
[0039] FIG. 3 is a simplified flow diagram showcasing the basic
functional operating steps followed by an embodiment with regard to
local operation of an isolation valve. As stated previously, for
local operation to occur it is necessary that the system be in
maintenance mode with all frac pumps disconnected from their
respective isolation valves. As shown, upon accepting an operator's
request to operate an isolation valve (302) the system checks each
isolation valve to determine if any valve is connected to a pump
(304). If no valves are connected to a pump, the valve operation is
allowed (308). However, if even a single valve is connected to a
pump then the system, in response to a local valve operation
request, displays a warning to the operator and valve operation is
prevented (306). This forces remote operation of the isolation
valves and pumps to ensure an increased level of operator
safety.
[0040] The safety interlock steps of the present embodiment may be
modified in accordance with the desired level of safety or risk
tolerance. One of ordinary skill in the art to which the invention
pertains will appreciate that greater or lesser levels of
redundancy may be utilized. For example, in another embodiment the
system prompts the operator at least once to confirm the desired
valve operation request before opening or closing the valve in
those conditions in which valve operation is allowed.
[0041] Although the embodiments described herein have involved
primarily systems for performing well stimulation using hydraulic
fracturing, the invention is also applicable to other industrial
applications that involve the use of pumps for delivery of high
fluid pressures and volumes to a single discharge manifold. For
example, the disclosed safety system may be utilized in the
high-pressure/volume processing, preparation, and delivery of
fluids in the food, chemical, and energy industries, and the like.
The present invention teaches safety features that benefit
operators in any such industrial fluid delivery situations.
[0042] The invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The present embodiments are therefore to be considered in
all respects as illustrative and not restrictive. Accordingly, the
scope of the invention is established by the appended claims rather
than by the foregoing description. All changes that come within the
meaning and range of equivalency of the claims are, therefore,
intended to be embraced therein. Further, the recitation of method
steps does not denote a particular sequence for execution of the
steps. Such method steps may therefore be performed in a sequence
other than that recited unless the particular claim expressly
states otherwise.
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